Electrodeposition of nickel



Patented Sept- 26,1950 I 2,524,010

UNITED STATES PATENT owner:

- ELECTRODEPOSITION F NICKEL Arthur H. Du Rose, Euclid, and Paul W. Moy,Cleveland, Ohio, assignors to The Harshaw Chemical Company, Cleveland,Ohio, a corporation of Ohio No Drawing. Application July 12, 1946,Serial No. 683,157

Claims. (0!. 204-49) This invention relates to electrodeposition ofdistinct, they will be separately described and metals and morespecifically to a process of and identified, solutions for use in aprocess 01. electrodepositing The substances oi the first addition agentclass, nickel, characterized in that the resulting nickel thosecontaining the C-:N group, are soluble electrodeposit is bright as itcomes from the plat- 6 to the extent of at least 0.1 gm. per liter inthe ing solution. More particularly, the present inplating solution (forexample in a solution convention has to do with the discovery ofcooperattaining 240 gm. per liter N1SO4.6H2O, 37.5 gm. ing additionagents suitable for use in an aqueous Y per liter of NiC12.6H2O and 37.5gm. per liter of acid nickel plating solution containing nickel HJBOa,remainder water) and are these consulfate or a mixture 01' nickelsulfate with nickel l0 taining from 1 to carbon atoms in the moleculechloride. exclusive of the carbon atom in the -CEN group,

We have now discovered that eqxcellent bright for example: deposits ofnickel can be produce by electrolyzing an aqueous, acid solution or anickel electroorganic cyanide brightener lyte oi the class consisting ofnickel sulfate and mixtures of nickel sulfate with nickel chloride,figfi gggt igx fgfigg if such solution also contains an eflective amountI Beta chloro propiomtrue (camccmcN) of each of two cooperating additionagents, one Betwbrommpropiomtme (BrHzccn-acN) of such addition agentsbeing an organic com- Alpha alpha bawmchlompmpiomtrue pound soluble inthe acid nickel solution to the (clmchcm extent 01' at least 0.1 gm. perliter, containing Ethylene cyanohydrm (HoCmCmC-N) not more than tencarbon atoms in the molecule, Lactomtme (CH3CHOHCN) exclusive of the CNgroup, and containing the Glycolomtrfle (HOCHZCN) group 451w attache? tocarbm} atom; and 3,3,3-trichloro-2-hydroxy-proplonitrlle the other ofsaid addition agents being a cyclic, (ChCCHOHCN) organic compoundsoluble in the acid nickel solu- Acrylomtrfle (naczcHcN) tion to theextent of at least 0.2 gm. per liter 11 B i i HCCHv and selected fromthe group consisting of sacgg hgg ga ggfi g gg g g charin, cyclicaromatic compounds and cyclo- 13 Ethyl cyanoacetate (C2H5OOCCH2CN)encode: capsularolefine compounds which contain the groupIsopropylcyamacetate o (CH3) :cnooccmcm fl p 15. Cyano-ethyl acetatemccmcmooccm l I; 16. Cyanoacetamide (NCCH2CONH2) 17. Butyl-cyano acetate(C4H700CCH2CN) wherein the carbon atom is nuclear carbon, andsuccmomtrfle [(011m) 2] in which compound each of the remaining nu- 9m-fl (c l-1 01c) clear carbon atoms carries a group of the class 211Benz cyanide me -1 cm consisting of hydrog n, methyl, ethyl, chl 21.3-phenyl-propionitrile (CcHtCzH4CN) bromine, CH0 and phenyl. The firstmentioned addition agent may be referred to as the organic 40 From theforegoing examples f h o anic cyanide brightener and should bemaintained in cyanides. it will be Seen that y are generally the platingsolution in a concentration from 0.1 i l irr sp iv f h yp f substituent.to 1.0 gm. per liter, preferably from 0.25 to 0.75 the number 0 carbons. Within he l mits gm per liter, while thesecond mentioned addi. ofsolubility, and whether saturated or unsatution agent which we prefer tocall a carrier or rated, aliphatic or aromatic. Examples are givenregulator should be maintained in the solution of simple aliphatic andaromatic cyanides, haloin a concentration 01' from 0.2 to 15.0 gm. pergen, hydroxy, amino and carboxy derivatives and liter, preferably from 1to '7 gm. per liter. esters oi the carboxy derivatives. Numerous ad-Since the two above mentioned classes oi ad ditional examples could begiven but the above dition agents are intrinsically and functionallywill be suflicientto illustrate the'class. Solubility ass-3010 is thechief requisite. There is a variation in the desirability of thesecompounds, some being used up sooner than others and some being moreexpensive or less readily available. Some have bet-' ter bright throwingpower (1. e., give better brightness in recesses) than others and somegive a more brilliant deposit or a more ductile deposit, than others;all, however, give bright deposits. Among the aliphatic organic cyanideswe prefer those having from 1 to 6 carbon atoms exclusive of the carbonin the CEN group.

' .4 the effective group which characterizes the other addition agentclass.

A conventional aqueous acid nickel bath in which the combined use of thetwo classes of eddi- The carriers or regulators, constituting the secondaddition agent class are soluble in the plating solution (for example,in a solution consisting of 240 grams of NiS04.6H2O. 37.5 gramsNiCls.6HzO, 37.5 grams of H130; and water to make a liter) tothe extentof at least 0.2 gram per liter. These include such materials as benzene,and thiophene sulfonic acids and salts thereof and halogen, methyl,ethyl, CH0 and phenyl substitution products of the foregoing, such asfor example:

B; Carriers or regulators Potassium and cobalt salts are usable as wellas the sodium and nickel salts indicated above.

From these examples it becomes clear that numerous single ringcompoundscontaining the effective group can be used with excellentresults,

whether aromatic, such as the benzene sulfonic acids or heterocyclicwitharomatic characteristics, such as thiophene sulfonic acid. Varioussubstituents on the ring structure are exemplified.

ring structures such as naphthalene sulfonic acidsare' effective toproduce brilliant deposits but are distinctly less desirable than thesingle ring type of compounds since they produce excessive brittlenessas compared with the single ring compounds.

It is to be understood that all statements made herein concerning thecapabilities of the addition agents presuppose the use of one or amixture of two or more from each class. The carrying agents produce adegree of brightness without any brightener but not enough to besatisfactory alone. The cyanides in the absence of the carrier producebright but brittle deposits. We prefer the use of the simpler and morecommon and readily available compounds and prefer to employ in eachaddition agent class only compounds devoid I tion agents will be foundto give improved results, as above indicated, consists of:

NiS04.6H 0 -450 grams per liter NiCl:.0Hs0- 15-76 grams per liter HaBOa15 grams per liter to saturation Sodium lauryl sulfate 0 to 1.0 gram perliter Cfillent density pp to 60 amp. per sq. it.

Temperature- Room to 170 F., preferably 120 to l Where this compound isreferred to, the material sold under the trade name oi "Duponol M. E.Dry" is to be understood. It is sold as the technical compound. Otherequivalent surface tension reducing agents may be used instead ofDuponol. Preparations known as Tergitol1 and Tergitol 08, sold byCarbide 8: Carbon Chemicals Company and said to be sodium secondaryalcohol sulfates, may be usedcl instead of Duponol. The quantitiesrequired are of the same or or.

In the above table giving the composition of a conventional bath, sodiumlauryl sulfate is added for the purpose of reducing the surface tensionin order to prevent pitting of the plate. The sulfates of normal primaryaliphatic alcohols, having from 8 to 18 carbon atoms, constitute a classof compounds preferred for use for this purpose.

The following table indicates a number of a..-

citlc examples of aqueous acid nickel plating solutions illustrative ofthe invention:

Table SolutionNo 1 2 3 NiSO BH O, momma,

HaB a. 8- 5 Sodium auryi Sulfate,

r Methyl trile acidsulfonsulfonamsulfonic Benzene pH, 3.6-4.0.Temperature, 120 F3140 F. Current density, 4000amps./sq./it.

All the above examples produced bright and ductile nickelelectrodeposits.

Having thus described our invention, what we claim is:

l. A process of producing bright deposits of nickel comprisingelectrolyzing an aqueous, acid solution of a nickel electrolyte of theclassconsisting of nickel sulfate and mixtures of nickel sulfate withnickel chloride, such solution also containing an effective amount ofeach of two cooperating addition agents, one of such addition agentsbeing ethylene cyanohydrin and being maintained in said solution inconcentration from 0.1 to 1.0 gm. per liter and the other of suchaddition agents being benzene monosulfonic acid and being maintained insaid solution in concentration from 0.2 to 10 gm. per liter.

2. A process of producing bright deposits of nickelcomprising'electrolyzing an aqueous, acid solution of a nickelelectrolyte of the class. consisting of nickel sulfate and mixtures ofnickel sulfate with nickel chloride, such solution also containing aneffective amount of each of two cooperating addition agents, one of suchaddition agents being ethyl cyanoacetate and the other of said additionagents being saccharine, ethyl cyanoacetate being maintained in saidsolution in concentration from 0.1 to 1.0 gm. per liter and saccharinebeing maintained therein in concentration from 0.2 to gm. per liter.

3. A method for electrodepositing nickel in the form of a deposit whichis bright as taken from the plating solution without further treatmentand which method comprises electrolyzing an aqueous, acid solution of anickel electrolyte of the class consisting of nickel sulfate andmixtures of nickel sulfate with nickel chloride, said solution alsocontaining cooperating addition agents capable of imparting brightnessto the deposit, one of said addition agents being an allphatic nitrilesoluble in said solution to the extent of at least 0.1 gram per literand having from 1 to 10 carbon atoms in the molecule exclusive of thecarbon atom in the CN group and the other of said addition agents beingan organic compound containing the group, and being soluble in saidsolution to the extent of at least 0.2 gram per liter, the carbon.

atom in said a. from 1 to 6 carbon atoms exclusive of the carbon atom inthe CN group.

5. A method for electrodepositing nickel in the form 01 a deposit whichis bright as taken from the plating solution without further treatmentand which method comprises electrolyzing an aqueous, acid solution of anickel electrolyte of the class consisting of nickel sulfate andmixtures of nickel sulfate with nickel chloride, said solution alsocontaining cooperating addition agents capable of imparting brightnessto the deposit, one of said addition agents being an organic nitrileselected from the group consisting of methyl cyanide, ethyl cyanide,beta-chloropropionitrile, beta-bromo-propionitrile, alpha, alpha,beta-trichloro-propionitrile, ethylene cyanohydrin, lactonitrile,glycolonitrile, 3,3,3-trichloro 2 hydroxy propionitrile, acrylonitrile,beta-amino-propionitrile, cyano acetic acid, ethyl cyanoacetate,isopropylcyanoacetate, cyanoethyl acetate, cyanoacetamide, butyl-cyanoacetate, succinonitrile, 3-phenyl-propionitrile and the other of saidaddition agents being an organic compound containing the group andselected from the class consisting of benzene mono-sulfonic acid,benzene disulfonic acids, sodium benzene monosulfonate, nickel benzenemonosulfonate, monochlor benzene monosulfonic acids, benzenemonosulfonamide, saccharine and its sodium salt, dichloro benzenedisulfonic acids, 2,5-dibromo benzene sulfonic acid, toluene sulfonicacids, benzaldehyde sul- REFERENCES CITED The following references areof record in the file of this patent:

UNI-TED STATES PATENTS Number Name Date 2,085,754 Hull July 6, 19372,238,861 Lind et al Apr. 15, 1941 FOREIGN PATENTS Number Country Date670,220 Germany Jan. 14, 1939 OTHER REFERENCES Metal Finishing, November1941, page 611 (an article by Linick) Metal Industry, December 11, 1942,pp. 379, 380

(an article by Henricks)

1. A PROCESS OF PRODUCING BRIGHT DEPOSITS OF NICKEL COMPRISINGELECTROLYZING AN AQUEOUS, ACID SOLUTION OF A NICKEL ELECTROLYTE OF THECLASS CONSISTING OF NICKEL SULFATE AND MIXTURES OF NICKEL SULFATE WITHNICKEL CHLORIDE, SUCH SOLUTION ALSO CONTAINING AN EFFECTIVE AMOUNT OFEACH OF TWO COOPERATING ADDITION AGENTS, ONE OF SUCH ADDITION AGENTSBEING ETHYLENE CYANOHYDRIN AND BEING MAINTAINED IN SAID SOLUTION INCONCENTRATION FROM 0.1 TO 1.0 GM. PER LITER AND THE OTHER OF SUCHADDITION AGENTS BEING BENZENE MONOSULFONIC ACID AND BEING MAINTAINED INSAID SOLUTION IN CONCENTRATION FROM 0.2 TO 10 GM. PER LITER.